TIME

Defining the Second The advancement of precision in time measurement has resulted in the adoption of new, more precise, definitions of the second. Prior to 1956, one second was defined as the fraction 1/86,400 of the mean solar day. From 1956 to 1967, it was the ephemeris second, defined as the fraction 1/31556925.9747 of the tropical year at 00h 00m 00s 31 December 1899. The second is currently defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.

LICK YOUR WOUNDS!

There are several types of wounds, and as a praetorian First Aider, you must know them all!

INCISED
clean cut, made by knife, blade, razor etc.
LACERATED
cut torn irregularly, made by machinery, barbed wire, claws etc.
PUNCTURE
made by nails, teeth (hopefully not human), garden forks [NB These can easily become infected!]
GRAZE
superficial layers of skin removed, leaving tender area. Can be easily infected due to grit etc. Often from sliding fall, such as motorbike incident.
GUNSHOT
small entrance wound, often larger exit wound. Note the major problem, is with internal damage!
CONTUSED
caused by fall or blow with a blunt object. There will be bruising. Main problem is with underlying damage, such as fractures.

SO YOUNG FIRST AIDERS... BE CAREFUL! AND ALWAYS REMEMBER YOUR ABC's!

Airway
Breathing
Circulation

THE 24-HOUR WORLD?

The earth spins on its axis every 24 hrs exactly, or does it?

Look at this simplified diagram. It shows the earth at two positions, half a solar year apart.

As the Earth moves around the Sun the axis of the earth stays tilted in the same direction, causing seasonal change.

On the globe positioned at 1^st of Jan, there is a point marked with a red dot, it is positioned roughly in the center of ‘africa’.

Now take special note, the red dot remains in the same position over 6months, this makes sense because after each 24hr period ends the red dot will return to the same position relative to the Earth’s axis… BUT! This leaves a problem, at position January the red spot at 0000hrs is in darkness, but six months later, at position June 15^th at 0000hrs the red spot is in brightest daylight!

Take a moment to imagine that, at midnight in winter it is dark – this seems fine. But, then in mid summer at midnight it is bright day! And this is not a consequence of the elongated daylight period… in this case we are talking about a point rougly on the equatorial line – where day and night periods change a minimal amount through the seasons!

We know that at Midnight 00:00 it must always be dark – so where is this problem arising from… Simply, and also strangely it arises from the problem of the supposed 24hr period!

The earth does not take exactly 24 of our clocked hours to revolve once on it’s axis. It takes something closer to 23hours and 57min. Thus over the period of six months, a sufficient amount of time has been ‘lost’ to effectively switch night and day – relative to our idea of time. Well fair enough, we don’t get the promised 24hr period.

But this leaves a bitter taste in the bucal cavity of a praetorian! If our earth spins ever 23hrs and 57min, and we must lose a large amount of time to keep clocks agreeing with light – HOW DO 24HR CLOCKS WORK?! Have those clock makers kept this a secret for a very long time, is this the reason why clocks always need reset!

Hmm, might explain the introduction of radio clocks which are constantly updated by a remote clock! Well, I shall leave you with this problem, whilst I shall fill my pipe full of fine tobacco.

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